Ad-tracking activity timing - AWS Elemental MediaTailor

Ad-tracking activity timing

With client-side reporting, the player must emit tracking events (beacons) with a level of precision. Using the MediaTailor client-side tracking schema, you can ensure that, for every avail, ad, companion, overlay, and tracking events, timing and duration information is present, and in different forms.

Use the following MediaTailor key/value pairs for the player to accurately reconcile ad-event activities, such as tracking events, with playback position:

HLS and DASH implement the value of startTime and startTimeInSeconds differently:

  • HLS - The startTime values are relative to the beginning of the playback session. The beginning of the playback session is defined as time zero. The ad's startTime is the sum of the cumulative values of all the EXT-INF segment durations leading up to the avail. The media-sequence number of the segment that the ad or tracking event falls on also corresponds to the adId or eventId in the client-side tracking response.

  • DASH:

    • Live/dynamic manifests - The startTime values are relative to the MPD@availabilityStartTime of the DASH manifest. The MPD@avaibilityStartTime is a timing anchor for all MediaTailor sessions that consume the stream.

    • VOD/static manifests - The startTime values are relative to the beginning of the playback session. The beginning of the playback session is defined as time zero. Each ad inside the avail is contained inside its own Period element. The Period element has a @start attribute with a value that's the same as the startTime values in the client-side tracking payload. The PeriodId also corresponds to the adId or eventId in the client-side tracking response.

Example : HLS

In the following example, the MediaTailor session started, and the following manifest is the first one served to the client:

#EXTM3U
#EXT-X-VERSION:6
#EXT-X-TARGETDURATION:6
#EXT-X-MEDIA-SEQUENCE:4603263
#EXT-X-DISCONTINUITY-SEQUENCE:0
#EXT-X-PROGRAM-DATE-TIME:2023-05-03T21:24:23.295678Z
#EXTINF:4.010667,
https://123.cloudfront.net/out/v1/index_1_34.ts
#EXT-X-PROGRAM-DATE-TIME:2023-05-03T21:24:27.306345Z
#EXTINF:4.010667,
https://123.cloudfront.net/out/v1/index_1_35.ts
#EXT-X-PROGRAM-DATE-TIME:2023-05-03T21:24:31.317012Z
#EXTINF:4.010667,
https://123.cloudfront.net/out/v1/index_1_36.ts
#EXT-X-PROGRAM-DATE-TIME:2023-05-03T21:24:35.327679Z
#EXTINF:4.010667,
https://123.cloudfront.net/out/v1/index_1_37.ts
#EXT-X-PROGRAM-DATE-TIME:2023-05-03T21:24:39.338346Z
#EXTINF:2.538667,
https://123.cloudfront.net/out/v1/index_1_38.ts
#EXT-X-DISCONTINUITY
#EXT-X-KEY:METHOD=NONE
#EXT-X-PROGRAM-DATE-TIME:2023-05-03T21:24:41.453Z
#EXTINF:2.0,
https://123.cloudfront.net/tm/asset_1080_4_8_00001.ts
#EXT-X-PROGRAM-DATE-TIME:2023-05-03T21:24:43.453Z
#EXTINF:2.0,
https://123.cloudfront.net/tm/asset_1080_4_8_00002.ts
#EXT-X-PROGRAM-DATE-TIME:2023-05-03T21:24:45.453Z
#EXTINF:2.0,
https://123.cloudfront.net/tm/asset_1080_4_8_00003.ts

In the client-side tracking JSON payload, the following values apply:

  • startTime: "PT18.581355S"

  • startTimeInSeconds: 18.581

  • availProgramDateTime: "2023-05-03T21:24:41.453Z"

  • adId: 4603269

Example : DASH

In the following example, the MediaTailor session gets a midroll in the manifest. Note that the @start attribute value of the second period, which is the ad period, has a value that's relative to the MPD@availabilityStartTime value. This value is the one that MediaTailor writes into the client-side tracking response startTime fields, for all sessions.

<?xml version="1.0" encoding="UTF-8"?>
<MPD availabilityStartTime="2022-10-05T19:38:39.263Z" minBufferTime="PT10S" minimumUpdatePeriod="PT2S" profiles="urn:mpeg:dash:profile:isoff-live:2011" publishTime="2023-05-03T22:06:48.411Z" suggestedPresentationDelay="PT10S" timeShiftBufferDepth="PT1M30S" type="dynamic" xmlns="urn:mpeg:dash:schema:mpd:2011" xmlns:scte35="urn:scte:scte35:2013:xml" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="urn:mpeg:dash:schema:mpd:2011 http://standards.iso.org/ittf/PubliclyAvailableStandards/MPEG-DASH_schema_files/DASH-MPD.xsd">
    <BaseURL>https://123.channel-assembly.mediatailor.us-west-2.amazonaws.com/v1/channel/my-channel/</BaseURL>
    <Location>https://123.cloudfront.net/v1/dash/94063eadf7d8c56e9e2edd84fdf897826a70d0df/MediaTailor-Live-HLS-DASH/channel/channel1/dash.mpd?aws.sessionId=794a15e0-2a7f-4941-a537-9d71627984e5</Location>
    <Period id="1683151479166_1" start="PT5042H25M59.903S" xmlns="urn:mpeg:dash:schema:mpd:2011">
        <BaseURL>https://123.cloudfront.net/out/v1/f1a946be8efa45b0931ea35c9055fb74/ddb73bf548a44551a0059c346226445a/eaa5485198bf497284559efb8172425e/</BaseURL>
        <AdaptationSet ...>
            ...
        </AdaptationSet>
    </Period>
    <Period id="1683151599194_1_1" start="PT5042H27M59.931S">
        <BaseURL>https://123.cloudfront.net/tm/94063eadf7d8c56e9e2edd84fdf897826a70d0df/fpc5omz5wzd2rdepgieibp23ybyqyrme/</BaseURL>
        <AdaptationSet ...>
            ...
        </AdaptationSet>
    </Period>
</MPD>

In the client-side tracking JSON payload, the following values apply:

  • startTime: "PT5042H27M59.931S"

  • startTimeInSeconds: 18152879.931

  • availProgramDateTime: null

  • adId: 1683151599194_1_1